For the following Contracting State(s) : AT, BE, CH, CY, DK, ES, FI, FR, GB, IE, IT,
LI, LU, MC, NL, PT, SE, TR
[0001] This application claims the benefit of U.S. Provisional Application No. 60/200,361,
filed April 28, 2000.
Field of the Invention
[0002] This invention relates to therapeutic compositions for use in treating diseases of
connective tissues in animals, more particularly, for use in treating osteoarthritis
in mammals, such as humans, dogs, cats, pigs, horses, cows, goats and sheep.
Background of the Invention
[0003] Arthritic diseases, characterized by the pain, inflammation and stiffness of the
joints leading to reduced range of mobility, are due to the degradation of connective
tissue (mainly cartilage) in joints. Such diseases particularly affect weight-bearing
joints such as the hips, knees, spine, ankles and feet and those joints with frequent
movement such as hands, arms and neck.
[0004] Osteoarthritis (OA) in particular is a degenerative disease of the joint cartilage
resulting in narrowing of the joint space and changes in the underlying bone (Barclay,
et al.,
The Annals of Pharmacotherapy, (May, 1998) 32: 574-79). OA is the most common form of arthritis among people and
it affects approximately one in ten people in North America. People of all ages can
get OA, but it more often affects older people and women. For example, 85% of the
age group 70 years or older is affected by OA (The Arthritis Society website, (http://www.arthritis.ca),
February 4, 2000, published by The Arthritis Society). OA is not limited to humans,
but occurs in other mammals such as horses, dogs, cats, mice and guinea pigs as well,
making OA one of the most common sources of chronic pain seen by veterinarians.
[0005] The cause of OA could be one or more of the following: nutritional deficiencies,
aging, long-term stress on joints (e.g. athletes, manual workers), old joint injuries
and genetic factors. The tissue that is directly affected is the cartilage covering
the end of long bones in joints that provide cushioning for the bones during movements.
In normal cartilage, chondrocytes (cartilage cells) maintain a balance between the
synthesis and degradation of cartilage matrix. However, when the degradation of cartilage
matrix exceeds that of synthesis, it leads to OA. When the disease progresses further,
bone underlying the articular cartilage in joints becomes exposed in certain places.
In addition, irregular bone growth occurs in the place of degenerating cartilage resulting
in rough bony alterations. As a result, the joint loses its smooth functioning leading
to joint pain, stiffness and swelling thus limiting mobility.
[0006] Cartilage is a unique tissue having cells (chondrocytes) embedded in their own secretions
which forms the cartilage matrix. The cartilage matrix is composed of a meshwork of
collagen fibrils and proteoglycan aggregates filling the space between collagen. Collagen
fibrils provide high tensile strength and proteoglycan aggregates provide internal
swelling pressure due to their hydrophilic nature. Cartilage cells are remarkable
in that they have the ability to proliferate while synthesizing and remodeling the
matrix around them. These two features provide the cartilage the ability to repair
itself during damage and replenish wear and tear.
[0007] Collagen fibrils are a major component of the cartilage matrix. Collagen is made
from amino acids, particularly lysine, proline and glycine. Fibrillar collagens are
triple helical molecules. The three α-chains of each collagen molecule are initially
produced as individual peptides which are further processed by the hydroxylation of
proline and lysine residues bound to the peptides. The hydroxyproline and hydroxylysine
so produced facilitate hydrogen bonding between the three α-chains, this being essential
for the formation of the triple helical structure (Linsenmayer, Collagen, Chapter
1 in
Cell Biology of Extracellular Matrix, Second Edition, Elizabeth D. Hay, ed., Plenum Press, N.Y. (1991) pp. 7-13). Unlike individual collagen
peptides (α-chains) that become easily digested by proteolytic enzymes, triple helical
collagen is extremely stable to proteolytic enzymes, heat and variations of pH. Therefore,
the most important step in collagen synthesis is the formation of the triple helical
structure by hydroxylation of amino acids in collagen α-chains. While the Linsenmayer
reference suggests that ascorbic acid and ferrous ions are cofactors in the hydroxylation
of proline and lysine to hydroxyproline and hydroxylysine respectively, Linsenmayer
does not suggest that a therapeutic composition comprising ascorbic acid and ferrous
ions would be useful in the treatment of osteoarthritis.
[0008] Proteoglycan aggregates are the other major component of the cartilage matrix. Cartilage
proteoglycans are macromolecules comprised of glycosaminoglycan (GAG) chains, such
as chondroitin sulphate and keratan sulphate, that are made up of repeating disaccharide
units containing aminosugars, attached to a core protein. Proteoglycans are in turn
attached to a backbone of hyaluronic acid, which is yet another GAG. Among GAGs of
cartilage, hyaluronic acid is unique in that it is an extremely large molecule with
about 25,000 repeating disaccharide units (in comparison, chondroitin sulphate and
keratan sulphate have only about 250 and 80 repeating disaccharide units respectively).
About 50% of hyaluronic acid and keratan sulphate are glucosamine.
[0009] Rheumatoid arthritis (RA) is a disease that has some similar symptoms to osteoarthritis,
but whose cause is considerably different. RA is known to be an autoimmune disease
(Maini, et al.,
Aetiopathogenesis of Rheumatoid
Arthritis. in
Mechanisms and Modes of Rheumatoid Arthritis, (1995) Academic Press Ltd. pp. 25-46), in which the immune system attacks body tissues
as if they were foreign invaders, culminating in inflammatory and destructive responses
in joints as well as other tissues. Although the exact cause of RA is not completely
understood, contributing factors are believed to include food allergies, pathogens,
leaky gut syndrome and hereditary factors. Because of the difference in cause of RA
as opposed to diseases of the connective tissues such as osteoarthritis, it is not
necessarily expected that treatment for RA would be effective against osteoarthritis
and the like.
[0010] A number of treatments for osteoarthritis and like diseases are commonly used. Most
of the treatments currently available are aimed towards reducing symptoms but do not
deal with the underlying tissue degradation. The use of steroids, corticosteroids
and other anti-inflammatory agents, such as non-steroidal anti-inflammatory drugs
(NSAIDs), for example, aspirin™, relieve symptoms and reduce pain but also do not
deal with the underlying tissue degeneration. NSAIDs may even speed up the progression
of OA (Rashad et al.,
The Lancet, (September, 1989) 2: 519-521, and, Herman et al., The Journal
of Rheumatology, (1986) 13: 1014-1018).
[0011] Therapies based on the regeneration of connective tissue, particularly cartilage,
are attractive long-term solutions to the problem of osteoarthritis. To this end,
there have been a number of disclosures of therapeutic compositions for the treatment
of arthritic diseases.
[0012] United States Patent Serial Number 3,683,076 issued on August 8, 1972 to Rovati discloses
pharmaceutical compositions comprising the glucosamine salts - glucosamine sulphate
and glucosamine hydroiodide - for the treatment of osteoarthritis and rheumatoid arthritis.
[0013] United States Patent Serial Number 5,587,363 issued on December 24, 1996 to Henderson
discloses therapeutic compositions comprising a synergistic combination of certain
aminosugars (glucosamine and its salts) with GAG's (chondroitin and its salts) for
the repair and replacement of connective tissue. Henderson suggests that Zn, Mn and
Vitamin C play a role in the synthesis of procollagen which is a building block of
collagen and that Cu, Fe and Vitamin C play a role in the synthesis of collagen from
procollagen. However, Henderson does not disclose synergistic compositions of ferrous
ion and an ascorbate. Henderson further suggests that glucosamine is a building block
in the synthesis of procollagen and that procollagen is a building block in proteoglycan
synthesis. However, it is generally accepted that glucosamine is not a building block
of procollagen, but is a building block of proteoglycan, while amino acids are the
building blocks of procollagen which becomes further processed to give rise to collagen.
[0014] Great Britain application Serial Number 2,317,109 published on March 16, 1998 discloses
a therapeutic composition for the treatment and repair of connective tissue in mammals
comprising glucosamine, chondroitin sulphate and one or both of ascorbic acid and
zinc sulphate. This application teaches that ascorbic acid and zinc sulphate serve
as catalysts in the metabolic pathways whereby cartilage and related tissues are produced
from the chondroitin sulphate and glucosamine building blocks. It further teaches
that one of ascorbic acid and zinc sulphate may be omitted from the composition. This
application does not teach a role for ascorbic acid and ferrous ion in the production
of collagen nor does it teach a synergistic combination of ferrous ion and ascorbic
acid in the production of connective tissue.
[0015] Barclay (Barclay, et al.,
The Annals of Pharmacotherapy, (May, 1998) 32: 574-79) teaches the use of glucosamine derivatives, such as the sulphate,
hydrochloride and chlorhydrate salts as well as N-acetylglucosamine, for the treatment
of osteoarthritis. Barclay suggests that glucosamine can be used in combination with
herbs, vitamins and minerals including the salts of magnesium, potassium, copper,
zinc and selenium and vitamins A and C. There is no disclosure of a therapeutic combination
of ferrous ion and ascorbic acid.
[0016] L'evenson (Levenson, G.E.,
Experimental Cell Research, (1969) 55: 225-228) teaches the effect of ascorbic acid on chondrocytes. Levenson
suggests that ascorbic acid plays a role in the production of cartilaginous material
but does not disclose a combination of ascorbic acid and ferrous ion.
[0017] Deal (Deal and Moskowitz, Rheum.
Dis. Clin. North. Am., (May, 1999) 25(2): 379-95) discloses nutraceuticals as therapeutic agents in
osteoarthritis comprising glucosamine and chondroitin sulphate. Glucosamine derivatives
have been shown to be as effective as NSAIDs in relieving the symptoms of OA without
having the adverse side effects of NSAIDs.
[0018] Sandy (Sandy, et al.,
Biochem. J., (1998) 335: 59-66) discloses the inhibitory effect of glucosamine on aggrecanase,
an enzyme that breaks down aggrecan in cartilage. Test formulations also contain ascorbic
acid but there is no discussion of its role. Sandy does not teach the combination
of ferrous ion and ascorbic acid in a therapeutic composition for the treatment of
osteoarthritis.
[0019] European Patent Serial Number 25,721 published on March 25, 1981 discloses an oral
medication for the treatment of rheumatoid arthritis comprising a mixture of a variety
of metals including ferrous ions in the form of ferrous sulphate. There is no discussion
of the role of ferrous ions, nor is there any suggestion that ascorbic acid may be
used in combination, nor is there any indication that the medication is effective
against diseases of the connective tissue such as osteoarthritis. As has been discussed
previously, rheumatoid arthritis is a different disease and it is not necessarily
expected that medications useful against rheumatoid arthritis would be effective against
diseases like osteoarthritis.
[0020] While the aforementioned compositions have been successful to varying degrees, none
have proven to be entirely satisfactory in the treatment of diseases of the connective
tissue like osteoarthritis. In particular, there is still a need for therapeutic compositions
that further facilitate the production of collagen alone or in combination with the
production of GAGs.
Summary of the Invention
[0021] It is therefore an object of this invention to provide compositions and methods useful
in treating a disease of connective tissue, particularly osteoarthritis, in animals,
preferably mammals, more preferably humans, dogs, cats, pigs, horses, cows, goats
and sheep.
[0022] It has now been found that a combination of ferrous ion and an ascorbate is surprisingly
effective at facilitating the production of connective tissue and is thus useful in
treating diseases of connective tissue. It has also been found that a glucosamine
derivative in combination with ferrous ion and an ascorbate is even more surprisingly
effective.
[0023] In accordance with the teachings of the present invention, there is provided a composition
for treating a disease of connective tissue comprising a therapeutically effective
amount of ferrous ion and a therapeutically effective amount of an ascorbate.
[0024] There is also provided a composition for treating a disease of connective tissue
comprising a therapeutically effective amount of ferrous ion, a therapeutically effective
amount of an ascorbate and a therapeutically effective amount of a glucosamine derivative.
[0025] There is still further provided a use of a composition comprising a therapeutically
effective amount of ferrous ion and a therapeutically effective amount of an ascorbate
for treating a disease of connective tissue. The use of ferrous ion and ascorbate
may be in combination with a therapeutically effective amount of a glucosamine derivative.
[0026] There is still further provided a use of a therapeutically effective amount of ferrous
ion and a therapeutically effective amount of an ascorbate for preparing a medicament
for treating a disease of connective tissue. The use of ferrous ion and ascorbate
may be in combination with a therapeutically effective amount of a glucosamine derivative.
[0027] There is yet still further provided a method of treating a disease of connective
tissue comprising administering to a patient suffering from the disease, a composition
comprising a therapeutically effective amount of ferrous ion and a therapeutically
effective amount of an ascorbate. The administration of ferrous ion and ascorbate
may also be in combination with the administration of a therapeutically effective
amount of a glucosamine derivative.
Description of Preferred Embodiments
[0028] The compositions of the present invention comprise ferrous ion and an ascorbate which,
surprisingly, act synergistically in the development of cartilage. Without being limited
to any particular mode of action, it is thought that the ferrous ion and the ascorbate
influence the production of collagen.
[0029] While it is thought that ascorbate and ferrous ion enhance cartilage development
by enhancing collagen synthesis, it is thought that glucosamine is a building block
for glycosaminoglycans of proteoglycans in the cartilage matrix. The presence of the
two types of cartilage enhancing agents further enhances total cartilage development.
The addition of a glucosamine derivative to the ferrous ion/ascorbate composition
provides a further enhanced effect on activity.
[0030] The term "treating" is used in a broad sense to encompass the amelioration of both
the cause and the symptoms of a preexisting disease or condition, and the prevention
or prophylaxis of the disease or condition.
[0031] Ferrous ions are preferably provided in the form of an inorganic or organic acid
salt wherein the ferrous ion is accompanied by a counter-ion to balance the charge.
Examples of inorganic counter-ions are sulphate, phosphate, nitrate, carbonate and
halide. A preferred inorganic counter-ion is sulphate. Ferrous sulphate is a preferred
inorganic form for ferrous ion. Examples of organic counter-ions are fumarate, gluconate,
ascorbate, tartarate, succinate, lactate, citrate and maleate. Three preferred organic
counter-ions are fumarate, ascorbate and gluconate. Ferrous fumarate, ferrous ascorbate
and ferrous gluconate are three preferred organic forms for ferrous ion. Ferrous ascorbate
has the advantage of providing both ferrous ion and ascorbate in the same compound.
[0032] Ferrous ion is present in the composition in an amount effective for promoting the
development of connective tissue in the body. The actual amount is not critical provided
it is sufficient to promote such development. The daily dosage of ferrous ion is preferably
in the range of about 0.5 mg to about 200 mg, more preferably in the range of about
2 mg to about 200 mg, yet more preferably in the range of about 10 mg to about 18
mg, and most preferably is about 15 mg.
[0033] An ascorbate is any species capable of providing the ascorbate ion. Examples include
ascorbic acid (Vitamin C) and salts of ascorbic acid including the potassium, sodium,
calcium, ferrous and manganese salt. Ascorbic acid, calcium ascorbate and ferrous
ascorbate are preferred. Ascorbic acid is the more preferred ascorbate.
[0034] Ascorbate is present in the composition in an amount effective for promoting the
development of connective tissue in the body. The actual amount is not critical provided
it is sufficient to promote such development. The daily dosage is preferably in the
range of about 40 mg to about 1000 mg, more preferably in the range of about 40 mg
to about 500 mg or about 100 mg to about 1000 mg, and most preferably is about 100
mg.
[0035] Glucosamine is an aminosugar. Examples of glucosamine derivatives are glucosamine
itself, glucosamine hydrochloride, glucosamine hydroiodide, glucosamine chlorhydrate,
glucosamine sulphate and N-acetyl glucosamine. Glucosamine hydrochloride and glucosamine
sulphate are preferred glucosamine derivatives.
[0036] The glucosamine derivative is present in the composition in an amount effective for
promoting the development of connective tissue in the body. The actual amount is not
critical provided it is sufficient to promote such development. The daily dosage is
preferably in the range of about 500 mg to about 3000 mg, more preferably in the range
of about 1000 mg to about 2000 mg, and most preferably is about 1500 mg.
[0037] In a particularly preferred embodiment, the composition consists essentially of an
effective amount of ferrous ion, an effective amount of an ascorbate and an effective
amount of a glucosamine derivative. Especially preferred is a composition consisting
essentially of an effective amount of ferrous sulphate, ferrous ascorbate or ferrous
fumarate, an effective amount of ascorbic acid and an effective amount of glucosamine
hydrochloride or glucosamine sulphate.
[0038] The dosage ranges described above are typically for humans. One skilled in the art
can readily determine appropriate doses for other animals.
[0039] The compositions of the present invention may also include other factors that may
be useful in treating a disease of connective tissue. These include glycosaminoglycans
(GAGs) such as chondroitin.
[0040] Other minerals and vitamins which have other therapeutic indications may be present
in the compositions. These include: zinc (in the form of zinc sulphate for example),
potassium, sodium, calcium, magnesium, vitamin D and vitamin E.
[0041] The compositions are preferably formulated together with a pharmaceutically acceptable
excipient or diluent. Such excipients or diluents as well as the methods of formulating
the compositions are well known to those skilled in the art. Cellulose, maltodextrin
and water are preferred.
[0042] In another particularly preferred embodiment, the composition consists essentially
of an effective amount of ferrous ion, an effective amount of an ascorbate, an effective
amount of a glucosamine derivative and a pharmaceutically acceptable excipient or
diluent. Especially preferred is a composition consisting essentially of an effective
amount of ferrous sulphate, ferrous ascorbate or ferrous fumarate, an effective amount
of ascorbic acid, an effective amount of glucosamine hydrochloride or glucosamine
sulphate, and water, cellulose or maltodextrin.
[0043] The compositions are generally formulated in a dosage form. Dosage forms include
powders, tablets, capsules, solutions, suspensions, emulsions and other forms that
are readily appreciated by one skilled in the art. The compositions may be administered
orally, parenterally, intravenously or by any other convenient method. Capsules and
tablets for oral administration are preferred.
[0044] The compositions of the present invention may also be admixed with a food or beverage
and taken orally in such a manner. Foods or beverages may help mask the flavour of
ferrous ion thus making the composition more palatable for consumption by humans or
other animals. Fortified foods and beverages may be made by adding the composition
of the present invention during the manufacturing of the food or beverage. Alternatively,
the consumer may add the composition to the food or beverage near the time of consumption.
Each ingredient of the composition may be added to the food or beverage together with
the other ingredients or separately from the other ingredients. Examples of foods
and beverages are cereals, snack bars, dairy products, fruit juices, powdered food
and dry powder beverage mixes.
[0045] There is also provided a method for treating a disease of connective tissue, such
as osteoarthritis, comprising administering a composition comprising an effective
amount of ferrous ion and an effective amount of an ascorbate to a patient suffering
from the disease. The method may further comprise administering the composition further
including an effective amount of a glucosamine derivative.
[0046] In such methods, the patient preferably receives from about 0.5 mg to about 200 mg
(more preferably from about 2 mg to about 200 mg) of ferrous ion per day and from
about 40 mg to about 1000 mg of the ascorbate per day. More preferably, the patient
receives from about 10 mg to about 18 mg of ferrous ion per day and from about 100
mg to about 1000 mg (or from about 40 mg to about 500 mg) of the ascorbate per day.
When a glucosamine derivative is also administered, it is preferably administered
in an amount from about 500 mg to about 3000 mg per day, more preferably in an amount
from about 1000 mg to about 2000 mg per day.
[0047] One skilled in the art will understand that, in a method for treating diseases of
connective tissue, daily dosage can be given all at once in a single dose or can be
given incrementally in several smaller dosages. Thus, the compositions of the present
invention can be formulated such that the recommended daily dose is achieved by the
administration of a single dose or by the administration of several smaller doses.
[0048] It is apparent to one skilled in the art that the compositions of this invention
can be included in a commercial package together with instructions for its use against
a disease of connective tissue, such as osteoarthritis. Such a package may be in the
form of a sachet, bottle or blisterpack but is not limited to such. Instructions are
normally in the form of a written material but are not limited to such.
Brief Description of the Drawings
[0049]
Figure 1 is a graph showing the dose dependent effect of ascorbic acid on cartilage
development.
Figure 2 is a graph showing the combined effect of ferrous sulphate (FeSO4) and ascorbic acid (AA) on cartilage development and showing the individual effect
of ferrous sulphate on cartilage development at a particular dose of ascorbic acid.
Figure 3 is a graph showing the combined effect of ferrous sulphate (FeSO4), ascorbic acid (AA) and glucosamine hydrochloride (GS-HCl) on cartilage development.
Figure 4 is a graph showing the dose dependent effect of zinc sulphate (ZnSO4) on cartilage development.
Figure 5 depicts micrographs of cartilage cultures after treatment with a composition
of the present invention and with prior art compositions.
Figure 6 is a graph comparing the effectiveness of a composition of the present invention
to the effectiveness of prior art compositions.
EXAMPLES
Example 1: Cell Culture Preparation
[0050] Cell cultures were prepared substantially as described in the prior art (S. Ekayanake
and B.K. Hall,
Int. J.
Dev. Biol., 38: 683-694 (1994)), the entire disclosure of which is hereby incorporated by reference.
In general, cartilage precursor cells from the developing limb bud of normal chick
embryos were isolated and a single cell suspension containing 2 × 10
7 cells/ml was prepared. For the production of micromass cultures, cells were plated
as 10 µl drops on to bottoms of 24-well plastic tissue culture plates and incubated
for 1 hour in a tissue incubator to allow cells to attach to the culture plate. Once
cells are attached, cultures were flooded with liquid culture medium comprising:
- a 3:1 mixture of Ham's F12 (from Gibco™) and BGJb (from Gibco™);
- 10% fetal bovine serum (from Gibco™);
- about 75 µg/ml of ascorbic acid; and
- other normal ingredients known to those skilled in the art.
This is the basic culture medium. Generally, the basic culture medium contains about
0.6 µg/ml ferrous sulphate due to its presence in the commercial medium. As can be
appreciated from this example, the basic cell culture medium also contains about 75
µg/ml of ascorbic acid that was added during the cell culture preparation as described
above. Cells were maintained in culture for up to 10 days. The culture medium that
cells grew in was changed daily. Under these conditions, cartilage precursor cells
produced cartilage tissue within 4 days, and the amount of cartilage present in cultures
gradually increased with time.
Example 2: Effect of Ascorbic Acid on Cartilage Development
[0051] Cultured cartilage cells were dosed with varying amounts of ascorbic acid. The amount
of cartilage produced was quantified using standard procedures such as the number
of cartilage nodules present per culture, the amount of cartilage matrix present per
culture as measured by alcian blue spectrophotometry, and microphotography. Figure
1 shows that ascorbic acid significantly enhances cartilage development in a dose-dependent
manner. The Control bar in Figure 1 represents the situation where no ascorbic acid
was added during the cell culture preparation. It is thought that cartilage development
in the Control experiment occurs because the cartilage cells themselves have a basal
level of ascorbic acid in them. The T
1 bar represents the results obtained when the basic culture medium is used, that is,
when 75 µg/ml of ascorbic acid is added during cell culture preparation as described
in Example 1. The T
2 bar represents the results obtained when an additional 75 µg/ml of ascorbic acid
is added to the basic culture medium to bring the total added ascorbic acid content
to 150 µg/ml.
Example 3: Effect of Ferrous Sulphate on Cartilage Development
[0052] Cultured cartilage cells prepared as described in Example 1 were dosed with varying
amounts of additional ferrous sulphate (test group) or no additional ferrous sulphate
(control group). It is thought that the control group shows cartilage development
due to the basal level of ferrous sulphate (about 0.6 µg/ml) and ascorbic acid (about
75 µg/ml) normally present in the basic culture medium. The amount of cartilage produced
was quantified using standard procedures as outlined in Example 2. As shown in Figure
2, the results indicate that, at a particular dose of ascorbic acid, ferrous sulphate
significantly enhanced cartilage development in a dose-dependent manner.
Example 4: Synergistic Effect of Ferrous Sulphate and Ascorbic Acid on Cartilage Development
[0053] Cultured cartilage cells were dosed with a combination of ferrous sulphate and ascorbic
acid at different concentrations. As shown in Figure 2, the results indicate that
when the dose of ascorbic acid is increased, there is a greater than expected increase
in cartilage development over the same dose range of ferrous sulphate. The results
indicate that the combination of ferrous sulphate and ascorbic acid exert a synergistic
effect on cartilage development and that the effect is dose dependent.
Example 5: Enhanced Effect of Ferrous Sulphate, Ascorbic Acid and Glucosamine Hydrochloride
on Cartilage Development
[0054] Cultured cartilage cells were dosed with varying concentrations of glucosamine hydrochloride
in combination with optimal doses of ferrous sulphate and ascorbic acid. The amount
of cartilage produced was quantified using standard procedures as outlined in Example
2. As shown in Figure 3, the results indicate that the combination of ascorbic acid
and ferrous sulphate have a synergistic effect on cartilage development and that this
effect was greater with increasing doses of glucosamine hydrochloride. The amount
of ferrous sulphate represented in Figure 3 (2 µg/ml) is the amount of additional
ferrous sulphate added and does not account for the basal level of ferrous sulphate
present in the basic culture medium. The amount of ascorbic acid (150 µg/ml) represents
the total amount of ascorbic acid including the 75 µg/ml normally added during the
cell culture preparation as described in Example 1.
Example 6: Effect of Zinc Sulphate on Cartilage Development
[0055] The effect of zinc sulphate on cartilage development was also tested. Cultured cartilage
cells prepared as described in Example 1 were dosed with varying concentrations of
zinc sulphate. The results are shown in Figure 4. There was no statistically significant
increase in cartilage development between the control group that contained no zinc
sulphate and the test groups that contained varying amounts of zinc sulphate. Therefore,
zinc sulphate does not have the same cartilage enhancing effect as ferrous sulphate.
Example 7: Effect of Other Metal Sulphates on Cartilage Development
[0056] Similar experiments to that of Example 6 were conducted using potassium sulphate,
cobalt (II) sulphate or nickel (II) sulphate instead of zinc sulphate. No statistically
significant increase in cartilage development was observed between the control group
and the test groups containing any of the metal sulphates. However, cobalt (II) sulphate
appeared to significantly reduce the amount of cartilage produced in a dose-dependent
manner.
Example 8: Comparison of Various Metal Sulphates with Ferrous Sulphate on Cartilage
Development
[0057] The combined effect of ascorbic acid with various metal sulphates (potassium sulphate,
cobalt (II) sulphate and nickel (II) sulphate) on cartilage enhancement was tested
using the procedure described in Example 1. The dose of ascorbic acid used was 150
µg/ml, which, as can be seen from Example 4, is a very effective dose. The amount
of ascorbic acid added to the cultures was kept constant (150 µg/ml). The concentration
of each of the metal ions was also kept constant (13 µM) and is comparable to the
concentration of ferrous ions in 2 µg/ml of FeSO
4·7H
2O. The amount of cartilage produced in each culture was measured using alcian blue
spectrophotometric methods. The results indicate that of all the metal sulphates tested,
only ferrous sulphate significantly enhanced the cartilage production when combined
with ascorbic acid.
Example 9: Comparison of Various Iron Salts
[0058] Similar experiment to that of Example 6 were conducted using ferrous ascorbate, ferrous
fumarate and ferric sulphate (containing Fe
3+, an oxidized form of iron). Both ferrous ascorbate and ferrous fumarate significantly
enhanced cartilage production indicating that, regardless of the form of the salt,
ferrous ion (Fe
2+) is capable of exerting cartilage enhancing effects. In contrast, there was no statistically
significant difference observed between the control cultures and the cultures treated
with ferric sulphate indicating the ineffectiveness of ferric ion (Fe
3+) in enhancing cartilage development.
Example 10: Comparison of a Composition of the Present Invention with Glucosamine-based
Products on the Market
[0059] Two leading brands of glucosamine-based products (Osteo Bi-Flex™ and Schiff™ glucosamine)
were tested in comparison to a composition according to the present invention using
an
in vitro cartilage cell culture system designed to study the ability of various compounds
to rescue degrading cartilage. This cartilage degradation monitoring system is an
expansion of the cell culture method described in Example 1.
[0060] In summary, cartilage cell cultures were established as described in Example 1 and
treated with the active ingredient mixture present in each of the above three products
purchased or prepared in cell culture grade. (The composition of the present invention
that was used contained 2 µg/ml ferrous sulphate, 150 µg/ml ascorbic acid and 100
µg/ml glucosamine hydrochloride. The composition using the active ingredients from
Schiff
TM glucosamine contained 100 µg/ml of glucosamine hydrochloride, 33 µg/ml of glucosamine
sulphate and 33 µg/ml of N-acetyl glucosamine. The composition using the active ingredients
from Osteo Bi-Flex
TM contained 100 µg/ml glucosamine hydrochloride, 100 µg/ml galactosamine and 100 µg/ml
glucuronic acid. (Galactosamine and glucuronic acid are the building blocks of chondroitin,
which is in the Osteo Bi-Flex
TM product.)) At day 4 when cartilage precursor cells have produced cartilage tissue,
cultures were fed with the same medium containing the active ingredients plus 1 µM
retinoic acid (RA). Retinoic acid has been previously shown to experimentally induce
degradation of cartilage in a manner similar to what is seen in osteoarthritis. Eighteen
hours after retinoic acid treatment, cultures were examined microscopically to evaluate
the degree of degradation that has occurred in the cartilage tissue of each of the
treatment groups, microscopic images were recorded using a digital image analysis
system and the actual amount of cartilage tissue present in each of the cultures was
quantified using alcian blue spectrophotometric methods.
[0061] Microscopic images of a representative culture from each of the experimental groups
are depicted in Figure 5. These cultures have been stained with alcian blue to visualize
cartilage tissue. The intensity of the blue stain corresponds to the amount of cartilage
present. The experimental groups are as follows:
Control |
Not treated with RA or any of the test compositions |
RA only |
Treated with RA but not with any of the test compositions |
RA + invention |
Treated with RA and with a composition of the present invention |
RA + Osteo Bi-FlexTM |
Treated with RA and with active ingredients in Osteo Bi-FlexTM formulation |
RA + SchiffTM |
Treated with RA and with active ingredients in SchiffTM formulation |
[0062] The amount of cartilage present in each of the groups after the experimental induction
of cartilage degradation is indicated in Figure 6. Figure 6 is a graph indicating
the ability of each of the compositions to rescue degrading cartilage.
[0063] Both Figures 5 and 6 indicate that retinoic acid induces substantial degradation
of cartilage as evidenced by the smaller amount of cartilage present in RA only treated
cultures at the end of the culture period in comparison to the control cultures that
were not treated with retinoic acid. However, even in the presence of RA, cultures
fed with the medium containing the composition of the present invention maintained
a higher level of cartilage production in comparison to RA only treated cultures and
also in comparison to cultures treated with RA plus the active ingredients present
in the other two prior art products. These results indicate the ability of compositions
of the present invention to rescue degrading cartilage, which is a feature very important
in treating the cause of osteoarthritis. These results also indicate the improved
effectiveness of the compositions of the present invention in comparison to prior
art formulations.
[0064] It is apparent to one skilled in the art that many variations on the present invention
can be made without departing from the scope or spirit of the invention claimed herein.
For the following Contracting State(s) : DE
[0065] This application claims the benefit of U.S. Provisional Application No. 60/200,361,
filed April 28, 2000.
Field of the Invention
[0066] This invention relates to therapeutic compositions for use in treating diseases of
connective tissues in animals, more particularly, for use in treating osteoarthritis
in mammals, such as humans, dogs, cats, pigs, horses, cows, goats and sheep.
Background of the Invention
[0067] Arthritic diseases, characterized by the pain, inflammation and stiffness of the
joints leading to reduced range of mobility, are due to the degradation of connective
tissue (mainly cartilage) in joints. Such diseases particularly affect weight-bearing
joints such as the hips, knees, spine, ankles and feet and those joints with frequent
movement such as hands, arms and neck.
[0068] Osteoarthritis (OA) in particular is a degenerative disease of the joint cartilage
resulting in narrowing of the joint space and changes in the underlying bone (Barclay,
et al.,
The Annals of Pharmacotherapy, (May, 1998) 32: 574-79). OA is the most common form of arthritis among people and
it affects approximately one in ten people in North America. People of all ages can
get OA, but it more often affects older people and women. For example, 85% of the
age group 70 years or older is affected by OA (The Arthritis Society website, (http://www.arthritis.ca),
February 4, 2000, published by The Arthritis Society). OA is not limited to humans,
but occurs in other mammals such as horses, dogs, cats, mice and guinea pigs as well,
making OA one of the most common sources of chronic pain seen by veterinarians.
[0069] The cause of OA could be one or more of the following: nutritional deficiencies,
aging, long-term stress on joints (e.g. athletes, manual workers), old joint injuries
and genetic factors. The tissue that is directly affected is the cartilage covering
the end of long bones in joints that provide cushioning for the bones during movements.
In normal cartilage, chondrocytes (cartilage cells) maintain a balance between the
synthesis and degradation of cartilage matrix. However, when the degradation of cartilage
matrix exceeds that of synthesis, it leads to OA. When the disease progresses further,
bone underlying the articular cartilage in joints becomes exposed in certain places.
In addition, irregular bone growth occurs in the place of degenerating cartilage resulting
in rough bony alterations. As a result, the joint loses its smooth functioning leading
to joint pain, stiffness and swelling thus limiting mobility.
[0070] Cartilage is a unique tissue having cells (chondrocytes) embedded in their own secretions
which forms the cartilage matrix. The cartilage matrix is composed of a meshwork of
collagen fibrils and proteoglycan aggregates filling the space between collagen. Collagen
fibrils provide high tensile strength and proteoglycan aggregates provide internal
swelling pressure due to their hydrophilic nature. Cartilage cells are remarkable
in that they have the ability to proliferate while synthesizing and remodeling the
matrix around them. These two features provide the cartilage the ability to repair
itself during damage and replenish wear and tear.
[0071] Collagen fibrils are a major component of the cartilage matrix. Collagen is made
from amino acids, particularly lysine, proline and glycine. Fibrillar collagens are
triple helical molecules. The three α-chains of each collagen molecule are initially
produced as individual peptides which are further processed by the hydroxylation of
proline and lysine residues bound to the peptides. The hydroxyproline and hydroxylysine
so produced facilitate hydrogen bonding between the three α-chains, this being essential
for the formation of the triple helical structure (Linsenmayer, Collagen, Chapter
1 in
Cell Biology of Extracellular Matrix, Second Edition, Elizabeth D. Hay, ed., Plenum Press, N.Y. (1991) pp. 7-13). Unlike individual collagen
peptides (α-chains) that become easily digested by proteolytic enzymes, triple helical
collagen is extremely stable to proteolytic enzymes, heat and variations of pH. Therefore,
the most important step in collagen synthesis is the formation of the triple helical
structure by hydroxylation of amino acids in collagen α-chains. While the Linsenmayer
reference suggests that ascorbic acid and ferrous ions are cofactors in the hydroxylation
of proline and lysine to hydroxyproline and hydroxylysine respectively, Linsenmayer
does not suggest that a therapeutic composition comprising ascorbic acid and ferrous
ions would be useful in the treatment of osteoarthritis.
[0072] Proteoglycan aggregates are the other major component of the cartilage matrix. Cartilage
proteoglycans are macromolecules comprised of glycosaminoglycan (GAG) chains, such
as chondroitin sulphate and keratan sulphate, that are made up of repeating disaccharide
units containing aminosugars, attached to a core protein. Proteoglycans are in turn
attached to a backbone of hyaluronic acid, which is yet another GAG. Among GAGs of
cartilage, hyaluronic acid is unique in that it is an extremely large molecule with
about 25,000 repeating disaccharide units (in comparison, chondroitin sulphate and
keratan sulphate have only about 250 and 80 repeating disaccharide units respectively).
About 50% of hyaluronic acid and keratan sulphate are glucosamine.
[0073] Rheumatoid arthritis (RA) is a disease that has some similar symptoms to osteoarthritis,
but whose cause is considerably different. RA is known to be an autoimmune disease
(Maini, et al.,
Aetiopathogenesis of Rheumatoid Arthritis, in
Mechanisms and Modes of Rheumatoid Arthritis, (1995) Academic Press Ltd. pp. 25-46), in which the immune system attacks body tissues
as if they were foreign invaders, culminating in inflammatory and destructive responses
in joints as well as other tissues. Although the exact cause of RA is not completely
understood, contributing factors are believed to include food allergies, pathogens,
leaky gut syndrome and hereditary factors. Because of the difference in cause of RA
as opposed to diseases of the connective tissues such as osteoarthritis, it is not
necessarily expected that treatment for RA would be effective against osteoarthritis
and the like.
[0074] A number of treatments for osteoarthritis and like diseases are commonly used. Most
of the treatments currently available are aimed towards reducing symptoms but do not
deal with the underlying tissue degradation. The use of steroids, corticosteroids
and other anti-inflammatory agents, such as non-steroidal anti-inflammatory drugs
(NSAIDs), for example, aspirin™, relieve symptoms and reduce pain but also do not
deal with the underlying tissue degeneration. NSAIDs may even speed up the progression
of OA (Rashad et al.,
The Lancet, (September, 1989) 2: 519-521, and, Herman et al.,
The Journal of Rheumatology, (1986) 13: 1014-1018).
[0075] Therapies based on the regeneration of connective tissue, particularly cartilage,
are attractive long-term solutions to the problem of osteoarthritis. To this end,
there have been a number of disclosures of therapeutic compositions for the treatment
of arthritic diseases.
[0076] United States Patent Serial Number 3,683,076 issued on August 8, 1972 to Rovati discloses
pharmaceutical compositions comprising the glucosamine salts - glucosamine sulphate
and glucosamine hydroiodide - for the treatment of osteoarthritis and rheumatoid arthritis.
[0077] United States Patent Serial Number 5,587,363 issued on December 24, 1996 to Henderson
discloses therapeutic compositions comprising a synergistic combination of certain
aminosugars (glucosamine and its salts) with GAG's (chondroitin and its salts) for
the repair and replacement of connective tissue. Henderson suggests that Zn, Mn and
Vitamin C play a role in the synthesis of procollagen which is a building block of
collagen and that Cu, Fe and Vitamin C play a role in the synthesis of collagen from
procollagen. However, Henderson does not disclose synergistic compositions of ferrous
ion and an ascorbate. Henderson further suggests that glucosamine is a building block
in the synthesis of procollagen and that procollagen is a building block in proteoglycan
synthesis. However, it is generally accepted that glucosamine is not a building block
of procollagen, but is a building block of proteoglycan, while amino acids are the
building blocks of procollagen which becomes further processed to give rise to collagen.
[0078] Great Britain application Serial Number 2,317,109 published on March 16, 1998 discloses
a therapeutic composition for the treatment and repair of connective tissue in mammals
comprising glucosamine, chondroitin sulphate and one or both of ascorbic acid and
zinc sulphate. This application teaches that ascorbic acid and zinc sulphate serve
as catalysts in the metabolic pathways whereby cartilage and related tissues are produced
from the chondroitin sulphate and glucosamine building blocks. It further teaches
that one of ascorbic acid and zinc sulphate may be omitted from the composition. This
application does not teach a role for ascorbic acid and ferrous ion in the production
of collagen nor does it teach a synergistic combination of ferrous ion and ascorbic
acid in the production of connective tissue.
[0079] Barclay (Barclay, et al.,
The Annals of Pharmacotherapy, (May, 1998) 32: 574-79) teaches the use of glucosamine derivatives, such as the sulphate,
hydrochloride and chlorhydrate salts as well as N-acetylglucosamine, for the treatment
of osteoarthritis. Barclay suggests that glucosamine can be used in combination with
herbs, vitamins and minerals including the salts of magnesium, potassium, copper,
zinc and selenium and vitamins A and C. There is no disclosure of a therapeutic combination
of ferrous ion and ascorbic acid.
[0080] Levenson (Levenson, G.E.,
Experimental Cell Research, (1969) 55: 225-228) teaches the effect of ascorbic acid on chondrocytes. Levenson
suggests that ascorbic acid plays a role in the production of cartilaginous material
but does not disclose a combination of ascorbic acid and ferrous ion.
[0081] Deal (Deal and Moskowitz,
Rheum. Dis. Clin. North. Am., (May, 1999) 25(2): 379-95) discloses nutraceuticals as therapeutic agents in
osteoarthritis comprising glucosamine and chondroitin sulphate. Glucosamine derivatives
have been shown to be as effective as NSAIDs in relieving the symptoms of OA without
having the adverse side effects of NSAIDs.
[0082] Sandy (Sandy, et al.,
Biochem. J., (1998) 335: 59-66) discloses the inhibitory effect of glucosamine on aggrecanase,
an enzyme that breaks down aggrecan in cartilage. Test formulations also contain ascorbic
acid but there is no discussion of its role. Sandy does not teach the combination
of ferrous ion and ascorbic acid in a therapeutic composition for the treatment of
osteoarthritis.
[0083] European Patent Serial Number 25,721 published on March 25, 1981 discloses an oral
medication for the treatment of rheumatoid arthritis comprising a mixture of a variety
of metals including ferrous ions in the form of ferrous sulphate. There is no discussion
of the role of ferrous ions, nor is there any suggestion that ascorbic acid may be
used in combination, nor is there any indication that the medication is effective
against diseases of the connective tissue such as osteoarthritis. As has been discussed
previously, rheumatoid arthritis is a different disease and it is not necessarily
expected that medications useful against rheumatoid arthritis would be effective against
diseases like osteoarthritis.
[0084] While the aforementioned compositions have been successful to varying degrees, none
have proven to be entirely satisfactory in the treatment of diseases of the connective
tissue like osteoarthritis. In particular, there is still a need for therapeutic compositions
that further facilitate the production of collagen alone or in combination with the
production of GAGs.
Summary of the Invention
[0085] It is therefore an object of this invention to provide compositions and methods useful
in treating a disease of connective tissue, particularly osteoarthritis, in animals,
preferably mammals, more preferably humans, dogs, cats, pigs, horses, cows, goats
and sheep.
[0086] It has now been found that a combination of ferrous ion and an ascorbate is surprisingly
effective at facilitating the production of connective tissue and is thus useful in
treating diseases of connective tissue. It has also been found that a glucosamine
derivative in combination with ferrous ion and an ascorbate is even more surprisingly
effective.
[0087] In accordance with the teachings of the present invention, there is provided a composition
for treating a disease of connective tissue comprising a therapeutically effective
amount of ferrous ion , a therapeutically effective amount of an ascorbate and a therapeutically
effective amount of a glucosamine derivative.
[0088] There is still further provided a use of a composition comprising a therapeutically
effective amount of ferrous ion, a therapeutically effective amount of an ascorbate
in combination with a therapeutically effective amount of a glucosamine derivative
for treating a disease of connective tissue.
[0089] There is still further provided a use of a therapeutically effective amount of ferrous
ion, a therapeutically effective amount of an ascorbate in combination with a therapeutically
effective amount of a glucosamine derivative for preparing a medicament for treating
a disease of connective tissue.
[0090] There is yet still further provided a method of treating a disease of connective
tissue comprising administering to a patient suffering from the disease, a composition
comprising a therapeutically effective amount of ferrous ion, a therapeutically effective
amount of an ascorbate in combination with a therapeutically effective amount of a
glucosamine derivative.
Description of Preferred Embodiments
[0091] The compositions of the present invention comprise ferrous ion and an ascorbate which,
surprisingly, act synergistically in the development of cartilage. Without being limited
to any particular mode of action, it is thought that the ferrous ion and the ascorbate
influence the production of collagen.
[0092] While it is thought that ascorbate and ferrous ion enhance cartilage development
by enhancing collagen synthesis, it is thought that glucosamine is a building block
for glycosaminoglycans of proteoglycans in the cartilage matrix. The presence of the
two types of cartilage enhancing agents further enhances total cartilage development.
The addition of a glucosamine derivative to the ferrous ion/ascorbate composition
provides a further enhanced effect on activity.
[0093] The term "treating" is used in a broad sense to encompass the amelioration of both
the cause and the symptoms of a preexisting disease or condition, and the prevention
or prophylaxis of the disease or condition.
[0094] Ferrous ions are preferably provided in the form of an inorganic or organic acid
salt wherein the ferrous ion is accompanied by a counter-ion to balance the charge.
Examples of inorganic counter-ions are sulphate, phosphate, nitrate, carbonate and
halide. A preferred inorganic counter-ion is sulphate. Ferrous sulphate is a preferred
inorganic form for ferrous ion. Examples of organic counter-ions are fumarate, gluconate,
ascorbate, tartarate, succinate, lactate, citrate and maleate. Three preferred organic
counter-ions are fumarate, ascorbate and gluconate. Ferrous fumarate, ferrous ascorbate
and ferrous gluconate are three preferred organic forms for ferrous ion. Ferrous ascorbate
has the advantage of providing both ferrous ion and ascorbate in the same compound.
[0095] Ferrous ion is present in the composition in an amount effective for promoting the
development of connective tissue in the body. The actual amount is not critical provided
it is sufficient to promote such development. The daily dosage of ferrous ion is preferably
in the range of about 0.5 mg to about 200 mg, more preferably in the range of about
2 mg to about 200 mg, yet more preferably in the range of about 10 mg to about 18
mg, and most preferably is about 15 mg.
[0096] An ascorbate is any species capable of providing the ascorbate ion. Examples include
ascorbic acid (Vitamin C) and salts of ascorbic acid including the potassium, sodium,
calcium, ferrous and manganese salt. Ascorbic acid, calcium ascorbate and ferrous
ascorbate are preferred. Ascorbic acid is the more preferred ascorbate.
[0097] Ascorbate is present in the composition in an amount effective for promoting the
development of connective tissue in the body. The actual amount is not critical provided
it is sufficient to promote such development. The daily dosage is preferably in the
range of about 40 mg to about 1000 mg, more preferably in the range of about 40 mg
to about 500 mg or about 100 mg to about 1000 mg, and most preferably is about 100
mg.
[0098] Glucosamine is an aminosugar. Examples of glucosamine derivatives are glucosamine
itself, glucosamine hydrochloride, glucosamine hydroiodide, glucosamine chlorhydrate,
glucosamine sulphate and N-acetyl glucosamine. Glucosamine hydrochloride and glucosamine
sulphate are preferred glucosamine derivatives.
[0099] The glucosamine derivative is present in the composition in an amount effective for
promoting the development of connective tissue in the body. The actual amount is not
critical provided it is sufficient to promote such development. The daily dosage is
preferably in the range of about 500 mg to about 3000 mg, more preferably in the range
of about 1000 mg to about 2000 mg, and most preferably is about 1500 mg.
[0100] In a particularly preferred embodiment, the composition consists essentially of an
effective amount of ferrous ion, an effective amount of an ascorbate and an effective
amount of a glucosamine derivative. Especially preferred is a composition consisting
essentially of an effective amount of ferrous sulphate, ferrous ascorbate or ferrous
fumarate, an effective amount of ascorbic acid and an effective amount of glucosamine
hydrochloride or glucosamine sulphate.
[0101] The dosage ranges described above are typically for humans. One skilled in the art
can readily determine appropriate doses for other animals.
[0102] The compositions of the present invention may also include other factors that may
be useful in treating a disease of connective tissue. These include glycosaminoglycans
(GAGs) such as chondroitin.
[0103] Other minerals and vitamins which have other therapeutic indications may be present
in the compositions. These include: zinc (in the form of zinc sulphate for example),
potassium, sodium, calcium, magnesium, vitamin D and vitamin E.
[0104] The compositions are preferably formulated together with a pharmaceutically acceptable
excipient or diluent. Such excipients or diluents as well as the methods of formulating
the compositions are well known to those skilled in the art. Cellulose, maltodextrin
and water are preferred.
[0105] In another particularly preferred embodiment, the composition consists essentially
of an effective amount of ferrous ion, an effective amount of an ascorbate, an effective
amount of a glucosamine derivative and a pharmaceutically acceptable excipient or
diluent. Especially preferred is a composition consisting essentially of an effective
amount of ferrous sulphate, ferrous ascorbate or ferrous fumarate, an effective amount
of ascorbic acid, an effective amount of glucosamine hydrochloride or glucosamine
sulphate, and water, cellulose or maltodextrin.
[0106] The compositions are generally formulated in a dosage form. Dosage forms include
powders, tablets, capsules, solutions, suspensions, emulsions and other forms that
are readily appreciated by one skilled in the art. The compositions may be administered
orally, parenterally, intravenously or by any other convenient method. Capsules and
tablets for oral administration are preferred.
[0107] The compositions of the present invention may also be admixed with a food or beverage
and taken orally in such a manner. Foods or beverages may help mask the flavour of
ferrous ion thus making the composition more palatable for consumption by humans or
other animals. Fortified foods and beverages may be made by adding the composition
of the present invention during the manufacturing of the food or beverage. Alternatively,
the consumer may add the composition to the food or beverage near the time of consumption.
Each ingredient of the composition may be added to the food or beverage together with
the other ingredients or separately from the other ingredients. Examples of foods
and beverages are cereals, snack bars, dairy products, fruit juices, powdered food
and dry powder beverage mixes.
[0108] There is also provided a method for treating a disease of connective tissue, such
as osteoarthritis, comprising administering a composition comprising an effective
amount of ferrous ion, an effective amount of an ascorbate and an effective amount
of a glucosamine derivative to a patient suffering from the disease.
[0109] In such methods, the patient preferably receives from about 0.5 mg to about 200 mg
(more preferably from about 2 mg to about 200 mg) of ferrous ion per day and from
about 40 mg to about 1000 mg of the ascorbate per day. More preferably, the patient
receives from about 10 mg to about 18 mg of ferrous ion per day and from about 100
mg to about 1000 mg (or from about 40 mg to about 500 mg) of the ascorbate per day.
The glucosamine derivative is preferably administered in an amount from about 500
mg to about 3000 mg per day, more preferably in an amount from about 1000 mg to about
2000 mg per day.
[0110] One skilled in the art will understand that, in a method for treating diseases of
connective tissue, daily dosage can be given all at once in a single dose or can be
given incrementally in several smaller dosages. Thus, the compositions of the present
invention can be formulated such that the recommended daily dose is achieved by the
administration of a single dose or by the administration of several smaller doses.
[0111] It is apparent to one skilled in the art that the compositions of this invention
can be included in a commercial package together with instructions for its use against
a disease of connective tissue, such as osteoarthritis. Such a package may be in the
form of a sachet, bottle or blisterpack but is not limited to such. Instructions are
normally in the form of a written material but are not limited to such.
Brief Description of the Drawings
[0112]
Figure 1 is a graph showing the dose dependent effect of ascorbic acid on cartilage
development.
Figure 2 is a graph showing the combined effect of ferrous sulphate (FeSO4 and ascorbic acid (AA) on cartilage development and showing the individual effect
of ferrous sulphate on cartilage development at a particular dose of ascorbic acid.
Figure 3 is a graph showing the combined effect of ferrous sulphate (FeSO4), ascorbic acid (AA) and glucosamine hydrochloride (GS-HCl) on cartilage development.
Figure 4 is a graph showing the dose dependent effect of zinc sulphate (ZnSO4) on cartilage development.
Figure 5 depicts micrographs of cartilage cultures after treatment with a composition
of the present invention and with prior art compositions.
Figure 6 is a graph comparing the effectiveness of a composition of the present invention
to the effectiveness of prior art compositions.
EXAMPLES
Example 1: Cell Culture Preparation
[0113] Cell cultures were prepared substantially as described in the prior art (S. Ekayanake
and B.K. Hall,
Int. J.
Dev. Biol., 38: 683-694 (1994)), the entire disclosure of which is hereby incorporated by reference.
In general, cartilage precursor cells from the developing limb bud of normal chick
embryos were isolated and a single cell suspension containing 2 x 10
7 cells/ml was prepared. For the production of micromass cultures, cells were plated
as 10 µl drops on to bottoms of 24-well plastic tissue culture plates and incubated
for 1 hour in a tissue incubator to allow cells to attach to the culture plate. Once
cells are attached, cultures were flooded with liquid culture medium comprising:
- a 3:1 mixture of Ham's F12 (from GibcoTM) and BGJb (from GibcoTM);
- 10% fetal bovine serum (from GibcoTM);
- about 75 µg/ml of ascorbic acid; and
- other normal ingredients known to those skilled in the art.
This is the basic culture medium. Generally, the basic culture medium contains about
0.6 µg/ml ferrous sulphate due to its presence in the commercial medium. As can be
appreciated from this example, the basic cell culture medium also contains about 75
µg/ml of ascorbic acid that was added during the cell culture preparation as described
above. Cells were maintained in culture for up to 10 days. The culture medium that
cells grew in was changed daily. Under these conditions, cartilage precursor cells
produced cartilage tissue within 4 days, and the amount of cartilage present in cultures
gradually increased with time.
Example 2: Effect of Ascorbic Acid on Cartilage Development
[0114] Cultured cartilage cells were dosed with varying amounts of ascorbic acid. The amount
of cartilage produced was quantified using standard procedures such as the number
of cartilage nodules present per culture, the amount of cartilage matrix present per
culture as measured by alcian blue spectrophotometry, and microphotography. Figure
1 shows that ascorbic acid significantly enhances cartilage development in a dose-dependent
manner. The Control bar in Figure 1 represents the situation where no ascorbic acid
was added during the cell culture preparation. It is thought that cartilage development
in the Control experiment occurs because the cartilage cells themselves have a basal
level of ascorbic acid in them. The T
1 bar represents the results obtained when the basic culture medium is used, that is,
when 75 µg/ml of ascorbic acid is added during cell culture preparation as described
in Example 1. The T
2 bar represents the results obtained when an additional 75 µg/ml of ascorbic acid
is added to the basic culture medium to bring the total added ascorbic acid content
to 150 µg/ml.
Example 3: Effect of Ferrous Sulphate on Cartilage Development
[0115] Cultured cartilage cells prepared as described in Example 1 were dosed with varying
amounts of additional ferrous sulphate (test group) or no additional ferrous sulphate
(control group). It is thought that the control group shows cartilage development
due to the basal level of ferrous sulphate (about 0.6 µg/ml) and ascorbic acid (about
75 µg/ml) normally present in the basic culture medium. The amount of cartilage produced
was quantified using standard procedures as outlined in Example 2. As shown in Figure
2, the results indicate that, at a particular dose of ascorbic acid, ferrous sulphate
significantly enhanced cartilage development in a dose-dependent manner.
Example 4: Synergistic Effect of Ferrous Sulphate and Ascorbic Acid on Cartilage Development
[0116] Cultured cartilage cells were dosed with a combination of ferrous sulphate and ascorbic
acid at different concentrations. As shown in Figure 2, the results indicate that
when the dose of ascorbic acid is increased, there is a greater than expected increase
in cartilage development over the same dose range of ferrous sulphate. The results
indicate that the combination of ferrous sulphate and ascorbic acid exert a synergistic
effect on cartilage development and that the effect is dose dependent.
Example 5: Enhanced Effect of Ferrous Sulphate, Ascorbic Acid and Glucosamine Hydrochloride
on Cartilage Development
[0117] Cultured cartilage cells were dosed with varying concentrations of glucosamine hydrochloride
in combination with optimal doses of ferrous sulphate and ascorbic acid. The amount
of cartilage produced was quantified using standard procedures as outlined in Example
2. As shown in Figure 3, the results indicate that the combination of ascorbic acid
and ferrous sulphate have a synergistic effect on cartilage development and that this
effect was greater with increasing doses of glucosamine hydrochloride. The amount
of ferrous sulphate represented in Figure 3 (2 µg/ml) is the amount of additional
ferrous sulphate added and does not account for the basal level of ferrous sulphate
present in the basic culture medium. The amount of ascorbic acid (150 µg/ml) represents
the total amount of ascorbic acid including the 75 µg/ml normally added during the
cell culture preparation as described in Example 1.
Example 6: Effect of Zinc Sulphate on Cartilage Development
[0118] The effect of zinc sulphate on cartilage development was also tested. Cultured cartilage
cells prepared as described in Example 1 were dosed with varying concentrations of
zinc sulphate. The results are shown in Figure 4. There was no statistically significant
increase in cartilage development between the control group that contained no zinc
sulphate and the test groups that contained varying amounts of zinc sulphate. Therefore,
zinc sulphate does not have the same cartilage enhancing effect as ferrous sulphate.
Example 7: Effect of Other Metal Sulphates on Cartilage Development
[0119] Similar experiments to that of Example 6 were conducted using potassium sulphate,
cobalt (II) sulphate or nickel (II) sulphate instead of zinc sulphate. No statistically
significant increase in cartilage development was observed between the control group
and the test groups containing any of the metal sulphates. However, cobalt (II) sulphate
appeared to significantly reduce the amount of cartilage produced in a dose-dependent
manner.
Example 8: Comparison of Various Metal Sulphates with Ferrous Sulphate on Cartilage
Development
[0120] The combined effect of ascorbic acid with various metal sulphates (potassium sulphate,
cobalt (II) sulphate and nickel (II) sulphate) on cartilage enhancement was tested
using the procedure described in Example 1. The dose of ascorbic acid used was 150
µg/ml, which, as can be seen from Example 4, is a very effective dose. The amount
of ascorbic acid added to the cultures was kept constant (150 µg/ml). The concentration
of each of the metal ions was also kept constant (13 µM) and is comparable to the
concentration of ferrous ions in 2 µg/ml of FeSO
4·7H
2O. The amount of cartilage produced in each culture was measured using alcian blue
spectrophotometric methods. The results indicate that of all the metal sulphates tested,
only ferrous sulphate significantly enhanced the cartilage production when combined
with ascorbic acid.
Example 9: Comparison of Various Iron Salts
[0121] Similar experiment to that of Example 6 were conducted using ferrous ascorbate, ferrous
fumarate and ferric sulphate (containing Fe
3+, an oxidized form of iron). Both ferrous ascorbate and ferrous fumarate significantly
enhanced cartilage production indicating that, regardless of the form of the salt,
ferrous ion (Fe
2+) is capable of exerting cartilage enhancing effects. In contrast, there was no statistically
significant difference observed between the control cultures and the cultures treated
with ferric sulphate indicating the ineffectiveness of ferric ion (Fe
3+) in enhancing cartilage development.
Example 10: Comparison of a Composition of the Present Invention with Glucosamine-based
Products on the Market
[0122] Two leading brands of glucosamine-based products (Osteo Bi-Flex
TM and Schiff
TM glucosamine) were tested in comparison to a composition according to the present
invention using an
in vitro cartilage cell culture system designed to study the ability of various compounds
to rescue degrading cartilage. This cartilage degradation monitoring system is an
expansion of the cell culture method described in Example 1.
[0123] In summary, cartilage cell cultures were established as described in Example 1 and
treated with the active ingredient mixture present in each of the above three products
purchased or prepared in cell culture grade. (The composition of the present invention
that was used contained 2 µg/ml ferrous sulphate, 150 µg/ml ascorbic acid and 100
µg/ml glucosamine hydrochloride. The composition using the active ingredients from
Schiff
TM glucosamine contained 100 µg/ml of glucosamine hydrochloride, 33 µg/ml of glucosamine
sulphate and 33 µg/ml of N-acetyl glucosamine. The composition using the active ingredients
from Osteo Bi-Flex
TM contained 100 µg/ml glucosamine hydrochloride, 100 µg/ml galactosamine and 100 µg/ml
glucuronic acid. (Galactosamine and glucuronic acid are the building blocks of chondroitin,
which is in the Osteo Bi-Flex
TM product.)) At day 4 when cartilage precursor cells have produced cartilage tissue,
cultures were fed with the same medium containing the active ingredients plus 1 µM
retinoic acid (RA). Retinoic acid has been previously shown to experimentally induce
degradation of cartilage in a manner similar to what is seen in osteoarthritis. Eighteen
hours after retinoic acid treatment, cultures were examined microscopically to evaluate
the degree of degradation that has occurred in the cartilage tissue of each of the
treatment groups, microscopic images were recorded using a digital image analysis
system and the actual amount of cartilage tissue present in each of the cultures was
quantified using alcian blue spectrophotometric methods.
[0124] Microscopic images of a representative culture from each of the experimental groups
are depicted in Figure 5. These cultures have been stained with alcian blue to visualize
cartilage tissue. The intensity of the blue stain corresponds to the amount of cartilage
present. The experimental groups are as follows:
Control |
Not treated with RA or any of the test compositions |
RA only |
Treated with RA but not with any of the test compositions |
RA + invention |
Treated with RA and with a composition of the present invention |
RA + Osteo Bi-Flex™ |
Treated with RA and with active ingredients in Osteo Bi-Flex™ formulation |
RA + Schiff™ |
Treated with RA and with active ingredients in Schiff™ formulation |
[0125] The amount of cartilage present in each of the groups after the experimental induction
of cartilage degradation is indicated in Figure 6. Figure 6 is a graph indicating
the ability of each of the compositions to rescue degrading cartilage.
[0126] Both Figures 5 and 6 indicate that retinoic acid induces substantial degradation
of cartilage as evidenced by the smaller amount of cartilage present in RA only treated
cultures at the end of the culture period in comparison to the control cultures that
were not treated with retinoic acid. However, even in the presence of RA, cultures
fed with the medium containing the composition of the present invention maintained
a higher level of cartilage production in comparison to RA only treated cultures and
also in comparison to cultures treated with RA plus the active ingredients present
in the other two prior art products. These results indicate the ability of compositions
of the present invention to rescue degrading cartilage, which is a feature very important
in treating the cause of osteoarthritis. These results also indicate the improved
effectiveness of the compositions of the present invention in comparison to prior
art formulations.
[0127] It is apparent to one skilled in the art that many variations on the present invention
can be made without departing from the scope or spirit of the invention claimed herein.